Scientists at The Jackson Laboratory (TJL) have long seen the need to train a cadre of research scientists in the complexity of the genetic basis of immunological and hematological problems using intact animal model systems. This philosophy, an integral part of the Laboratory's Strategic Plan, has dictated the ongoing expansion of the overall training program at TJL. The Jackson Laboratory requests funding for continuation of its well-established postdoctoral research training program in immunology and hematology. Ten members of the TJL Research Staff form an interdisciplinary pool of trainee preceptors who are investigating gene regulation, cell development and math models in hemopoietic and immunological pathways in the mouse. Experimental work in genetically-defined animal models provides the opportunity to test hypotheses regarding the genetic basis of immunological and hematological disorders and to model new diagnostic and therapeutic modalities. These types of analyses are made possible by the availability of the Laboratory's unparalleled resource base of special inbred, spontaneous and induced-mutant mice. TJL Postdoctoral program (4 trainees). Trainees devote their major effort to bench research, and are integrated into TJL seminars, workshops, and research interest groups. They are required to write fellowship applications, and present their results both at in-house interest groups and international meetings. Their progress is overseen by a formal Training Committee, each member of which acts as an informal sub-mentor, or liaison, for several trainees. On completion of training, participants will be qualified to engage in creative, independent research in hematology and immunology at a university, research institution, or in industry. These well-trained scientists will be given the tools to unlock the mysteries of immunological and hematological diseases in mice, which could then solve the same problems in humans. The resultant knowledge will serve the public health interests by developing treatments for Type 1 diabetes, anemia, leukemia, stem cell defects, rheumatoid arthritis, and a host of other diseases. The primary training facility is TJL, a private, independent research center. TJL is an NIH Basic Cancer Research Center, raises 3 million mice annually, and has held NIH research training grants since 1956.